Update Python version in manpage workflow to 3.13 (#1462)

Author: bocekm

.github/workflows/generate_manpage.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v5
         with:
-          python-version: 3.13.3
+          python-version: 3.13
 
       - name: Install dependencies
         run: |